US2686414A

US2686414A - Skin treating apparatus

Info

Publication number: US2686414A
Application number: US159436A
Authority: US
Inventors: Robert H Griffin
Original assignee: TANNERS RES CORP
Current assignee: TANNERS RES CORP; TANNERS' RESEARCH Corp
Priority date: 1950-05-02
Filing date: 1950-05-02
Publication date: 1954-08-17
Anticipated expiration: 1971-08-17

Description

Aug. 17, 1954 R. H. GRIFFIN 2,686,414

SKIN TREATING APPARATUS Filed May 2, 1950 ll Sheets-Sheet 1 Inventor: Robert H. Griffin his Attorney I I N .I .IIIII II. I I I I 3 I I IIIIIII I RI. m .l. I i 2 a 1 hN H I III. a "1 LWLW 1 F m ..I 1 n. ma H I mm I Q I! I II 3 fi III||| I Q I.. R IIIIII 2 I I. k mu wc /U II IP MN MN I I I Q h n Mk I 0 NM kb I I \k Mk hh k mi I MQ m aw 5 m In L l QOOQOOOOOOOOOOOQOOD 0900000000000000000 Aug 17, 1954 R. H. GRIFFIN sxm TREATING APPARATUS 1 1 Sheets-Sheet 2 Filed May 2, 1950 III. llll III II II HIIIIIIIIllllllllllllllllllm lfllllllll'dlllllllll I' Inventor: Robert H. Griffin 5, WWW

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his Attorney R. H. GRIFFIN SKIN TREATING APPARATUS Aug. 17, 1954 11 Sheets-Sheet 3 Filed May 2, 1950 Inventor; Robert. H. Griffin his Attorney Aug. 17, 1954 R; H. GRIFFIN sxm TREATING APPARATUS 11 Sheets-Sheet 4 Filed May 2, 1950 Inventor: Robert H. Griffin his Attorney Aug. 17, 1954 R. H. GRIFFIN 14 SKIN TREATING APPARATUS Robert H. Griffin his Attorney Filed May 2, 1950 R. H. GRIFIN SKIN TREATING APPARATUS 11 Sheets-Sheet 6 Inventor:

his Aflorney Robert H. Griffin R. H. GRIFFIN 2,686,414

SKIN TREATING APPARATUS l1 Sheets-Sheet 7 2 u 4 8 V1 M 0 i m m w m m w r m m fi m 7 6- m M M. i M M M T H 1 1 0% I G A 98 H 2 m I l 5 3 H h H H U U n m 1 I t r 3 8 mm 4 u w 3 a H H M R M W.

Aug. 17, 1954 Filed May 2, 1950 i I NH. 22/46 FIG.

R. H. GRIFFIN 2,686,414

SKIN TREATING APPARATUS Aug. 17, 1954 Filed May 2, 1950 11 Sheets-Sheet 8 AMPLIFIER 3O K.G. 050. I32

CHANNEL 4 CHANNEL CHANNEL 5 CHANNEL 2 CHANNEL 3 FIG. 14

CUTTER-OUT HEAD F J1 AMPLIFIER AND J1 I SELECTOR unn /a4 J1 AMPLIFIER AND swl'rcnme SOLENOID LI EGTOR UNIT U UNIT 9 VALVE CUTTIERIN HEAD FIG. 15

Inventor:

Robert H. Griffin his Attorney Aug. 17, 1954 R. H. GRIFFIN 2,635,414

SKIN TREATING APPARATUS Filed May 2, 1950 11 Sheets-Sheet 9 R3 in; In

R2 was FIG. 17

Inventor:

Robert H. Griffin his Attorney Aug. 17, 1954 R. H. GRIFFIN SKIN TREATING APPARATUS Filed May 2, 1950 11 Sheets-Sheet l0 1954 R. H. GRIFFIN SKIN TREATING APPARATUS 11 Sheets-Sheet 11 Filed May 2, 1950 rm ms Y & Wm he e 1mm H \I. 9 e w 5 v R y B H I l/ I. V//V///////////////WE FIG. 20

his A'l'rorney Patented Aug. 17, 1954 UNITED STATES PATENT OFFICE SKIN TREATING APPARATUS Robert H. Griffin, Yonkers, N. Y., assignor to Tanners Research Corporation, New York, N. Y., a corporation of Delaware Application May 2, 1950, Serial No. 159,436

30 Claims.

This invention relates to the treatment of sheet material and particularly to apparatus for treating skins, hides and other sheet material, such as disclosed in my copending applications Serial No. 703,571, filed October 16, 19%, and Serial No. 42,652, filed August 5, 1948, of which the present invention is an improvement.

The primary object of the invention is to provide improved apparatus for subjecting sheet material to one or more treatments as a continuous process.

An object of the invention is to provide improved apparatus for treating both faces of sheet material in their entireties in a single pass.

Another object of the invention is to provide apparatus for continuously processing a succession of individual sheets of material wherein the opposite faces of the sheets are subjected to the same or dilferent treatments in individual cycles automatically varying with and determined by the characteristics of each sheet.

An additional object of the invention is to provide apparatus for treating sheet material having means for exteriorly gripping the material to a rotary work support, while enabling the exposed face of the material to be treated in its entirety.

Another object of the invention is to provide apparatus for treating sheet material having electronic means actuated by the material for automatically controlling its treatment, wherein the control is such as to permit successive sheets of different characteristics to be fed to the apparatus in rapid and close succession and treated with like uniformity.

A further object of the invention is to provide apparatus for treating sheet material wherein the treating devices are cyclically operated by an electronic control which is readily adjustable to encompass desired variations in the operative cycle.

A further object of the invention is to provide skin treating apparatus for treating the opposite faces of a skin in their entireties in a single pass, in which a skin is carried through the apparatus on a series of continuous conveyors and positively transferred from one to the succeeding conveyor.

An additional object of the invention is to provide apparatus for unhairing and fleshing the corresponding faces of a skin in their entireties in a single pass, wherein the skin is so acted on by the treating means as to contain the hair and fiesh removed as waste matter from the skin within relatively narrow confines, enabling the hair 2 and flesh to be segregated and directed into separate hoppers from which they are readily removed as discrete by-products, thereby avoiding the usual necessity both for interrupting operation of the beam-house machines while waste is removed from them and the floor of the beamhouse, and for subsequently separating the contaminated waste, in which hair and flesh are commingled, into its valuable by-product ingredients.

Another object of the invention is to provide skin treating apparatus utilizing rotary cutters for removing undesired natural matter from a skin, wherein means are provided for sharpening the cutters in situ.

Other objects and advantages of the invention will appear hereinafter in the detailed de scription, be particularly pointed out in the appended claims and illustrated in the accompanying drawings, in which:

Figure 1 is a front elevational view of a preferred embodiment of the skin treating apparatus of the present invention;

Figure 2 is a side elevational view of the apparatus, taken from the left side of Figure 1, with a portion of the side of the frame broken away to more clearly depict the discharge conveyor;

Figure 3 is a side elevational view of the apparatus, taken from the right side of Figure 1;

Figure 4 is a vertical sectional view, taken along the lines q-4 of Figure 1;

Figure 5 is a vertical sectional view, taken along the lines 55 of Figure 1;

Figure 6 is a fragmentary view on an enlarged scale showing the construction of the feed conveyor;

Figure 7 is a fragmentary view on an enlarged scale of the fluid pressure device for discharging a skin from the feed conveyor, the view being taken on the same section as Figure 5;

Figure 8 is a fragmentary front elevational view on an enlarged scale of the upper portion of the control box of the apparatus with the cover removed to show the details of construction of the magnetizable recorder disk and related mechanism;

Figure 9 is a side elevational view on an enlarged scale of the control unit of Figure 8 with portions removed and shown in section to more clearly illustrate certain of the details of construction;

Figure 10 is a vertical sectional view on the scale of Figure 8, taken along the lines Ill-40 of Figure 9;

Figure 11 is a fragmentary vertical sectional view on an enlarged scale, taken along the lines 3 ll-l I of Figure 8, showing in cross-section a typical magnetic head and the disposition of its components relative to the recorder disk;

Figure 12 is a fragmentary vertical sectional view, taken along the lines l2l2 of Figure 11;

Figure 13 is a fragmentary horizontal sectional view, taken along the lines l3-l3 of Figure 11;

Figure 14 is a schematic view showing the relation between the electronic control mechanism and the cyclically operating elements of the apparatus;

Figure 15 is a block diagram of the control circuit of a typical cutter;

Figure 16 is a wiring diagram typical of the power supply and control circuits by which each of the several cutters is actuated;

Figure 17 is a wiring diagram of an'alternative circuit for actuating the fluid pressure device by which a skin may be detached from the feed conveyor;

Figure 18 is a fragmentary front elevational view on an enlarged scale showing the sharpening mechanism for sharpening the blades of the fieshing cylinder;

Figure 19 is a vertical sectional view on an enlarged scale, taken along the lines |9l9 of Figure 18;

Figure 20 is a vertical sectional view on the scale of Figure 19, taken along the lines 20-40 of Figure 18, with the sharpening unit shifted'into position to sharpen the lower fieshing cutter;

Figure 21 is a fragmentary horizontal sectional view, taken along the lines 2 l2l of Figure 18;

Figure 22 is a horizontal sectional View, taken along the lines 22-22 of Figure 21; and

Figure 23 is a fragmentary vertical sectional view, taken along the lines 2323 of Figure '1 and showing the intergearing of the first grip roll and the unhairing drum.

Referring now in detail to the drawings in which like reference characters designate like parts, the apparatus of'the present invention is applicable to sheet material and is especially adapted to handle a succession of skins, hides and like individual or non-continuous sheets of material. The apparatus of the illustrated embodiment of the invention is particularly designed, as were those of the aforementioned copending applications, to perform upon a skin the so-called beam-house operations in which excess natural matter or tissue, predominantly hair and flesh, is removed from the opposite sides of a skin, usually at the outset of thetanning process. The apparatus is comprised of a frame I having a base 2 and laterally or transversely spaced sides or uprights 3. While the frame may be made of weldments or other suitable construction, the illustrated frame is cast, with the sides 3 connected across their upper ends by transverse I beams 4 which may'project beyond either one or both sides of'the apparatus andwith a connecting longitudinal I-beam 5, may also serve as tracks for supporting hoists, such as shown in my copending application Serial No. 126,546, filed November 10, 1949.

The illustrated apparatus is designed to treat the opposite sides, faces or surfaces of a skin, designated on the drawings as S, at separate positions or zones along its path of travel through the apparatus. There is provided for this purposea movable work support at each position in the form of a rotary'supporting or back-up drum or cylinder, the one for presenting for treatment the hair face of the skin, numbered 6, hereinafter referredto as the unhairing drum and that for 4 the flesh face, numbered 1, hereinafter termed the fieshing drum. Each of these drums is mounted on a shaft 8 extending between the sides 3 of the frame and rotatably mounted in journals 9 positioned in openings 10 in the sides. For better arrangement and to facilitate handling a succession of skins of varying lengths, the drums are preferably positioned somewhat apart, with one spacesomewhat behind and above the other to accommodate the associated mechanisms, as well as for better control of the travel of the skins. For feeding and carrying skins through the apparatus, use is made of a system or series of endless belt or like conveyors. Since a skin will normally be wet from previous treatment when introduced into the apparatus and its flesh face 'or side in that condition has better adherence to a belt, it is preferred first to treat the opposite or hair face or side of a skin. Accordingly, the first position or zone at which a skin is treated is occupied by the first, upperor unhairing drum 6 to which it is fed by a feed or infeed endless belt conveyor Ii. As it passes beyond the stations of the treating devices associated with the unhairing drum, the skin, still in contact with the feed conveyor, is supported on an intermediate conveyor I2 encircling the second, lower or fleshing drum 1, by which it is carried to and around the latter drum. The skin is then transferred to a third or end conveyor 13, by which it is deposited on a fourth or discharge conveyor [4, which carries the skin out of the apparatus. Of the several conveyors, the feed and intermediate conveyors are driven by the supporting drums which they encircle and the end and discharge conveyors by drive pulleys or rollers l5 and 16, respectively, the several conveyors riding therebeyond on idler pulleys or rollers.

It has heretofore been contemplated to provide suction for causing a skin to be gripped to a feed conveyor to ensure proper feeding to the first treating position. It has now been found that the adhesion between the wet face of a skin and a belt conveyor is sufficient to enable a skin to travel up a considerable incline without slipping, and this factor has been utilized in-determining the position of the upper idler roller ll of the feed conveyor relative both to the unhairing drum 6 'and'the outer or feed idler roller [8.

To maintain-the proper tension on the several belts, one of the idler rollers of each is made adjustable'transversely of its axis in the conventional manner. It will also be noted that each of theconveyor belts has associated with it a beltcentering device l9 by which its position'axially of the-associated drums" or rollers is maintained. The device iscomprised of an idler roller 20 extending transversely across and underlying a return portion of the associated belt. This roller issupported by a post 2| mounted on the frame and rotatable about an axis normal to the confronting face of the belt. Projecting from the post below the transverse roller and opposite the direction 'oftravel of the belt, are a pair of upslanting, divergent arms 22 carrying at their end rollers 23, which are'disposed normal to the belt and embrace its opposite sides. With this device, creepage of the belt toward either side will displace the confronting of the arm-carried rollers 23 and, through it, -rotate the post 2| a like amount. The corresponding angular displacement of thetransverse'roller 20 applying a component of force to the belt opposing the creepage, the roller will" then 'drive'the belt toward the opposite side until both are restored to their normal positions.

At both the unhairing and fleshing positions, a skin supported on the corresponding supporting drum through the related of the conveyor belts is treated by a pair of bladed cylinders or cutters, the cylinders of each pair being positioned at spaced stations about or along the periphery of the drum. In order of position, the first and second bladed cylinders or cutters, 24 and 25, respectively,

comprising the unhairing pair, are designed to r0- tate oppositely with their unhairing blades 25 converging adjacent the unhairing drum, the first cutter thus rotating counter-clockwise and the second, clockwise, in the View of Figure 5. This same relation obtains in the third and fourth cutters, 21 and 28, respectively, of the fieshing drum, their fieshing blades 29 also converging adjacent the fleshing drum and the cutters rotating clockwise and counter-clockwise, respectively. Thus, the first and third cutters act in the direction of travel of a skin, while the second and fourth cutters oppose this travel.

Working on a skin in convergent directions, the cutters of each pair, alone, could not be utilized for spreading or stretching a skin taut, as is essential if the treatment is to be substantially uniform. However, such action is not contemplated, each cutter being intended to work on substantially one-half of a skin and, except when so working, being moved to inoperative position, in the manner to be hereinafter described. It is therefore essential that other means be provided which will coact with each cutter during its operative cycle to spread or stretch a skin therebetween and, at the same time, will enable the exposed surface of the skin to be treated in its entirety by each pair of cutters in its passage through their treating zone. This is here accomplished by the provision for each drum of a pair of grip rolls, one leading and the other following the associated pair of cutters relative to the direction of travel of a skin through the apparatus. The leading or first and trailing or second grip rolls of the unhairing drum are numbered 3'0 and 3|, respectively, and the corresponding or third and fourth rolls of the fieshing drum, 30a and 3 I a, respectively. Of these grip rolls, the first grip roll 30 bears directly against a skin, while the remaining grip rolls all bear on a skin through an intervening conveyor belt. As such direct engagement might cause a skin to stick to the grip roll 30, the latter is preferably intergeared with the unhairing drum 6, as shown in Figure 23, such that the grip roll has a slightly higher peripheral speed, an advance of as little as one-quarter of an inch per revolution having proved adequate to prevent sticking. The other grip rolls presenting no such problem, are driven through their associated conveyors.

The grip rolls of each pair are positioned about the associated drum in spaced stations between which are included the stations of the associated cutters. Additionally, the rolls of each pair are disposed relative to the path of travel of the related belt so as to be partially wrapped or encircled by the belt as it reaches and leaves the drum. Partially wrapped by the related belt outwardly of the drum, each grip roll changes the direction of the belt and imparts to it a reverse or S-bend outwardly of the adjacent cutter. By pressing or urging its belt against the drum intermediate the reverse bend, each grip roll by virtue of the partial wrap, assisted by the arcuate path described by the belt about the drum between the roll and the adjacent cutter, applies a force to the belt and to a skin carried thereon which opposes the force of the adjacent cutter. If the angular distance about the associated drum between each grip roll and its adjacent or companion cutter is not less than the roll and cutter, alone, will coact or cooperate during the operative cycle of the cutter, effectively to grip a skin to the drum and to stretch the skin taut therebetween. This minimum distance between grip roll and coacting cutter must be maintained with respect to the second and succeeding grip rolls 3 I, 3811 and 310., which act on a skin through an intervening conveyor. However, the first grip roll 30, which directly engages a skin, is preferably provided with opposed, helical ribs, such as disclosed in my aforementioned copending applications Serial Nos. 703,571 and 42,652, and with the grip provided by the ribs, can be set at a less distance from the associated cutter 26. The first grip roll having opposed helical ribs, the illus-- trated cutters having blades of like configuration, and the setting-out of a skin so obtained on the unhairing drum 6 being maintained intermediate the drums by gripping a skin during its transfer between opposing conveyors, the coaction of the rolls and cutters spreads the skin both longitudinally and laterally and presents it in smooth condition for action by the cutters, enabling the presented face of the skin to be treated uniformly and in its entirety in each treating zone.

It has been mentioned that th grip rolls are yieldably or resiliently urged against the associated of the supporting drums, 6 and 1. Due

" to space limitations, two types of mountings have been employed in the illustrated embodiment for mounting the shafts 32 of the grip rolls, both of which provide the desired action, one type being utilized for the leading grip roll 30 0f the unhairing drum 6 and the other type on the remaining three grip rolls, 3|, 30a and 31a. This first type consist of a yoke 33 bolted or otherwise attached to the outer face of each of the sides 3 of the frame I, the yokes having jaws 34 at their inner ends confronting the drum journal-mounting openings In in the sides, between which jaws, journals 35 carrying the ends of the grip roll shaft 32 are slidably mounted. To the upper end of each journal, and projecting substantially radially of the unhairing drum, is rotatably connected the lower end of a connecting rod 36 having a threaded lower portion carrying a pair of adjustable lock nuts 31. Above the nuts, the rod is encircled by a coil spring 38 bearing against a lower plate 39, in which the upper end of the. rod is slidably received, the plate being connected and fixedly spaced relative to an upper. plate 40 by bolts 4| encircled by sleeves 42. The upper plate 40 is, in turn, adjustably spaced from the upper end of the yoke by a threaded bolt 43 and suitable nuts 44. To guide the plates, 39 and 40, and at the same time permit ready disassembly of the mounting, the ends of the plates. crosswise of the yoke, are slidably received in. slots 45 formed in abutments 46 fixed to and projecting inwardly of the sides of the yoke. With this construction, the springs 38 of the companion mountings are enabled to provide the yieldable or resilient force necessary for the grip roll 30 to press the feed conveyor 1 l against the unhairing drum 6, and the force so applied is readily adjusted through the adjusting lock nuts 31. As the grip roll is designed to be driven through the unhairing drum 6 by the intergearing of Figure 23, it is necessary that this driving engagement be 7 maintained-cesiume'yieiainger the-grip roll. is aeeampiished by utilizing intergearing sumcieiitly deep toothed to accommodate the compaiatively small recipiocable movement of the grip roll relative to the drum.

The other type of grip roll mounting for the rolls 3|, 39a and 31a, is comprised of 'a pair of flanged beams' ll, each having one end pivo'tally attachedto the-outer face of 'one of the-'sides3, and having bolted to it, intermediate'its ends, one of the journals 48 carrying the ends of the -sha'fts 320: the associated grip roll. The other'orouter end of the 'beain'is pivotallyconnected to the end of a threaded bar telescoping within a partially threaded. tube '50, the latter having its outer end slidably received in a yoke l"th'r'ough which it is attached to the frame. Adjustment ofthe length of the telescoping unit is obtained throughan internally threaded collar 52 rotatably connected to the threaded tube and threadedly engaging the threaded bar. The outer ends of the'coinpanion' beams of each grip ro11"are resiliently or 'yieldably urged inwardly, correspondingly moving the grip roll and causing it to'p'iess the-confronting portion of the associated belt against'its supporting drum, by coil springs-53 encirclingthe threaded tube 58, the force of which is'adjustable through adjusting l'ock nuts 54,"carrie'd by the threaded tube.

"To obtain the intermittent operation required of the several skin treating cutters, 24, 25, Hand 28, in order to limit the operation of each to a portion of the surface of a skin, provision is made for'moving the cutters substantially radially of their associated drums and for normally holding them in their out or inoperative positions. Mounting of the cutters to permit such movement is obtained in a manner similar to that employed for the first grip roll 30. There is thus provided for each cutter a pair of wires 55, each fixed to an opposite outer face of the sides'3 and having its open end, confronting the drum openings ill, provided with confronting jaws 56, between which are slidably mounted. journals 57 carrying the ends of the shafts 58 of the cutters. Yieldable urging of the cutters toward their associated d'rumsand adjustment of this force is obtained by the same type of mechanism as' that utilized for the aforementioned grip roll, there being provided for each of the journals a partially threaded connecting rod 5.; rotatably connected to the journal and projectible or slidable at its upper-end through a lower plate '69 agairist'the force of a rod encircling spring El. This plate is, in turn, spacedly connected to an upper plate 62 to which is attached the lower end of a piston rod'63 of a piston (not shown) reciproca-ble in a fluid pressure cylinder 64. On the'application of fluid pressure to the cylinders of each cutter through solenoid actuated control valves65, the piston rodsand connected structure forming the sliding units of companion mountings areenabled to be moved radially of theassociated drum and correspondingly move the cutter carried thereby. Guiding'of the upper and lower plates, 50 and GI, of each unit in their sliding or reciprocable movement,-without interference with disassembly, is accomplished by abu'tments 69 projecting inwardly of the sides'of the yoke and'groo'ved 'to receive the lateral ed'gesof the plates.

The drives by which the various movingparts of' the apparatus are driven a're'best shownin Figures 1, 3 and 4. For driving the several cutters, there is preferably provided, to one side of-the frame I, a drive stand 61in which'are mounted,

fit!

- lubricating elements (not shown).

on' concrete'blocks 68,'a pair of electric motors 69, one for driving the unhairing cutters, 24 and 25, and theother the fleshing cutters, 21 and'28. These in'otors drive their associated cutters by multiple V-belts 10 through drive pulleys H mountedon the framework 12 of the drive stand, and eac'h-drivably connected to one of the cutters through a universalshaft 13 to allow for the reciprocable movement of the cutters. The drive -pulleys H are of such size and so connected'to their'associated motors through idler pulleys 14' as to cause the related cutters of each pair to be rotated in the aforementioned divergent directions and-at the speeds required for most emcientoperation. A. C. motors being-generally used because of the relative availability of such current, 'any' desired variations in the speeds of the cutters may 'be 'obta'ined in suitable manner, such as by the-substitution of drive pulleys of different sizes.

The other rotary-elements or members of the apparatus may bedriven by a'single 'motor unit 15 mounted on one of the sides 3 'of the frame, the unit including an A. C. electric motor (not shown) driving through vari-pulleys (not shown) by which the speed of its drive or drive member 76 can be varied over a wide range. The drivable connection between the drive unit and the several members is preferably obtained by dual chain drives 11 drivably connecting the drive member 16 directly to the unhairing and fleshing drums, 6 and i, and to the-drive pulleys, l5 and I6, of the end and discharge conveyors, I3 and [4, through single chain drives '18 driven off the unhairing drum. To drive the drums in opposite directions, an idler is required for the main drive and for this purpose an idler sprocket 79 is carriedby'a bracket 80 mounted in an aperture 8| adjacent the upper end of the contiguous side of the frame. The tension of the main drive may be maintained by adjustable tensioning pulleys 82 and the chain maybe-supported, intermediate the rotary members, by guide sleeves 83, incorporating the usual guide rollers and wick chain As shown in Figure 1, the supporting drums and their associated mechanisms are offset toward one side of the frame-in order to accommodate the chain drives.

'With the several conveyor belts, H, i2 and I3, and'the discharge conveyor l4 driven through their associated supporting drums and drive pulleys, a skin laid by'an operator flesh side down on the feed conveyor H at the feed end of the apparatus, will be carried by that conveyor over its upper idlerroller I! under the leading grip roll 30 of the unhairing drum 6 and over the drum to the first and second cutters, 24 and 25. After the skin'has passed the second cutter, it is met by the intermediate conveyor I2 which is adapted toabut or engage and merge in path with the feed conveyor from that point to the fleshing drum. The skin is therefore gripped betweenthese conveyors as it passes the trailing grip roll 32 of the unhairing drum and the leading grip roll30a of the fleshing drum. Intermediate the latter *g'rip' roll and the third cutter 21, the feed and intermediate conveyors separate, the feed conveyor returning over'suitable idler rollers tothe feed end of the apparatus-and the intermediate conveyor encircling the fieshing drum 1 and carrying the skin past the third and fourth cutters, 2'I'a-nd 28. Beyond the fourth'cutter'ZB, the path or the "intermediate-conveyor merges with that of the end conveyor l3, such that the skin is gripped therebetween as it passes under the last grip roll 3Ia. Beyond this roll, the paths of the two conveyors separate, the skin thereafter being carried by the end conveyor until deposited on the discharge conveyor I4 for discharge from the apparatus.

It will be evident that the skin, when passing over the unhairing drum 6, has its hair side exposed and is reversed in transfer to the fleshing drum 7 to there expose its flesh side. There being considerable adhesion between the flesh side of the skin and the feed conveyor II, provision is made for positively disconnecting or detaching the skin from the feed conveyor at the point of separation of the latter from the intermediate conveyor I2. This is here accomplished by a fluid pressure device 84, preferably in the form of the water spray shown in detail in Figure 7. As there illustrated, the device comprises an open-bottomed box 85 mounted on the frame I by a bracket 86 and in which is slidably received an open-topped box member 81, the box member having its bottom wall 88 covered by a layer of rubber or like material 89, which extends the width of and is adapted to abut against the inner face of the feed conveyor, As indicated in Figures 6 and '7, the bottom wall 88 and its contact layer 89, as Well as the feed conveyor, are perforate or foraminous to permit passage of fluid therethrough against the flesh side of the skin. This fluid is supplied to the box 85, under suflicient pressure to detach or disconnect the skin from the feed conveyor, through a conduit 90, the flow of fluid being controlled by a solenoid actuated valve 9|.

Detachment of a skin at the proper time from the intermediate and end conveyors, I2 and I3, to ensure its transfer to the discharge conveyor It is accomplished by the provision of a pair of scrapers 92, one of which extends across each of the conveyors beyond the last grip roll 3Ia and resiliently bears on the outer face of the conveyor. To supplement the action of the scrapers, there is preferably provided, just ahead of each, a water or other fluid spray (not shown) for injecting fluid between the skin and the associated conveyor, across the width of the latter. These sprays may be cyclically actuated in the manner hereinafter described for so actuating the spray 84. However, since not subject to the space limitations of the spray 84, these supplemental sprays need not act through the conveyors but may be positioned to direct fluid at a slant against the outer faces of their conveyors. Since no fluid need pass through the intermediate and end conveyors, I2 and I3, they are preferably made of solid rubber or like suitable material. The discharge conveyor I4 may be of like construction, but has been shown as a slatted contiuous conveyor which, after passing through an opening 93 in the adjacent side of the apparatus, follows an inclined ram 94 to bring the skin to suitable height for loading on horses or other carriers used in transferring the unhaired and fleshed skins to succeeding tanning operations.

As a skin is treated by the cutters in its passage through the apparatus, by-product waste is produced in the form Of hair and flesh in the two treating zones. It is presently the practice in a tannery to allow this waste to accumulate on the floor of the beam-house, from whence it is shovelled into containers and removed at frequent intervals, this necessitating frequent hosing of the floor with consequent interruption of the r freely rotatable.

operation of the beam-house machines. In the instant apparatus, the cutters of each pair act convergently and throw their wastes toward each other, each thus assisting the other in directing the waste and by this coaction limiting the path over which the waste is thrown. Accordingly, accumulation of waste on the floor is here readily avoided by directing the waste, as it is severed from the skin, into hoppers, one an unhairing hopper 95 for the unhairing drum 6 and the other, a fleshing hopper 96 for the fleshing drum 1. Each hopper projects over and partly encloses both of the associated cutters, with its upper end portion 91 open only on the side confronting the cutters. These upper end portions are connected in each hopper to funnel sections 38 which lead, for the fleshing hopper to a discharge chute and for the unhairing hopper, to an open-bottomed bin I00, there to be collected for removal in suitable containers, or a continuous water-carrier disposal system.

Driven at all times during the operation of the apparatus by a pair of motor 69, the cutters are designed automatically to treat or operate upon a skin in cycles timed in relation to passage or travel of a skin through the apparatus. To this end, there may be mounted on the side of the apparatus opposite that of the drive mechanism a control box IOI, having a removable cover I02, in which is housed an electronic control or timer unit. To avoid any possibility of breakage of the elements of the unit by shock, the control box is connected to the side of the frame through shock-proof mountings I03. The upper portion of the control box is occupied by an electromagnetic timing device, the central element of which is a recorder or control disk I04, keyed or pinned to a rotating drive shaft I05 carried by a split journal I06 mounted on spaced crossbars I01 in the box. This shaft projects outside the box and there carries a sprocket wheel I08 through which it is drivably connected by a reduction chain drive I09 to the drive I6 of the motor unit I5. The recorder disk is intended to encompass, in a full revolution, the passage of skin from a reference point through the several treating zones, the reduction ratio in the illustrated embodiment being about 3.3:1.

Ranged or disposed about the recorder disk I04 and overlying its periphery are a plurality of magnetic heads III), each carried by a head holder or mounting bracket III slidably mounted radially of the recorder disk on a substantially U-shaped, slotted or bifurcated slide piece or block II2, the slide piece embracing the opposite sides and overlying the periphery of a stationary positioning plate H3 and being connected, on either side of the plate, to spaced guide arms I I4. The stationary plate is, in turn, fixed to an annular flange II5 of a sleeve bearing II 6 about which the guide arms II4 are adapted to rotate. This sleeve bearing also serves as a bearing for the drive shaft I05 of the recorder disk I04, within which the shaft is To prevent induced rotation of the sleeve bearing, the end portion of the bearing, beyond the guide arms II 4, is held by the split journal I06 which, in turn, is anchored to the spaced cross-bars I01 by a base plate II'I. Adjacent the sprocket wheel end of the shaft I05, the base plate supports a pillow block II8 carrying a second sleeve bearing H9 for journaling that end of the shaft. As shown, the pairs of guide arms of the several magnetic heads are interleaved and spaced at progressively greater distances from the positioning plate II3 such that they are individually adjustable about the plate, the inner ends I20 of the inner arms serving as spacers for the outer arms. For fixing any of the magnetic heads at a predetermined position circumferentially of the positioning plate, the periphery of the latter is grooved and adapted to receive an adjusting screw I2I threadedly engaging. the slide piece II2 of each head, .and extending radially of the plate, tightening of this screw setting the particular head at any desired circumferential position. Adjustment of the spacing between each magnetic head and the periphery of the recorder disk I 5 is provided by a second adjusting screw I22, rotatably connected to or collared by an oifset or lug I23 formed in the associated head holder III and threadedly engaging the slide piece, this screw also being disposed substantially radially of both disk and plate.

It has been mentioned that the control disk I04 is rotated'at a predetermined or given ratio or speed relative to the linear speed of the conveyor belts and that a complete rotation of the disk includes the entire pass of a skin. The lineal relationship so fixed between the periphery of the disk and the conveyors, which causes the periphery to move in coordination, consonance or accordance with the linear movement of the conveyors, is utilized to enable the disk and its associated heads electronically to control the operation of the several operating devices in timed relation to the passage of a skin through the apparatus. For this purpose, the body I24 of the recorder or control disk is made of stainless steel or other non-magnetic material, and its periphery is formed of a continuous band, tape or strip I25 of magnetic material which is plated or otherwise applied to the disk. Each of the magnetic heads IIO confronting the magnetic strip is formed of an open-bottomed shell I26, housing a cylindrical, split magnetic core'or ring I21 disposed normal to the control disk and having a minimum magnetic gap for sharp definition. About the core is the usual winding I28 from which extend leads I29. These electromagnets carried by the magnetic heads are severally employed to apply a magnetic signal to the magnetic tape, pick up pulses or impulses from the signal and erase the signal, during a single rotation of the disk. The picked up pulses are, in turn, employed to operate, energize or actuate, through electronic circuits, the solenoid' actuated valves 65 and' GI, controlling theoperation of the cutters and water sprays.

Referring now to Figure 14, there is there shown diagrammatically the relationship between-the operating devices and the electromagnetic control. For starting a cycle of operation, there is employed a suitably sensitive electric switch, preferably in the form of a photoelectric cell I30, mounted on the frame I at one side of the feed conveyor I I in advance oftheunhairing drum 6 and its associated operating devices, and positioned to be energized by a beam of light passing across the outer face of the conveyor, the beam, in turn, being so positioned relative to the conveyor that it will be interrupted or intercepted by any part of a skin on the conveyor. The cell I30 is electrically connected through an amplifying circuit I3! to one of the magnetic heads which serves as a recording or inducing head I32 and induces magnetism in the tape I25, themagnetized portion or magnetic signal or recording commencing. at the moment the light beam is interrupted by the leading edge of a skin and continuing along the tape until the light beam is restored by passage of the trailing edge of a skin past the photoelectric cell. Travelling at a fixed linear speed relative to the conveyor and having its limits set by the time of passage of the leading and trailing edges of a skin past a fixed reference point, the photoelectric cell I30, the magnetic signal is a scale image of a skin and corresponds, reflects or is related directly to the skin undergoing treatment in both limits and speed of travel. Accordingly, by providing for the several operating devices pickup heads, disposed circumferentially relative to the recording head I32 in positions determined by the linear positions of the operating devices relative to the photoelectric cell, the electromagnetic control is enabled to control the action of the operating devices in timed relation to the passage of a particular skin through the apparatus.

An image of the skin undergoing treatment, the magnetic signal on the tape I first reaches the pair of magnetic heads controlling the first or leading unhairing cutter 24, the cutter-in or operative head being numbered I33 and the cutter-out or inoperative head I34, both of which are connected to the cutterthrough an electronic control circuit designated as Channel 1 on the corresponding block of Figure 1'4. Next, the signal reaches the cutter-in and out heads, I35 and I36, respectively, of the second unhairing cutter 25 and later, the cutter-in and out heads, I3! and I38, respectively, of the third or first fleshing cutter 2? and those, I30 and I40, respectively, of the fourth or second flashing cutter 28. In advance of the in head I37 of the third cutter, the magnetic signal passes the spray-on or operative head I4I of the water spray BI and, if one is'employed, later an ofi head I52 for the spray, such as shown in Figure 8. On the diagram of Figure 14, in which the spray has only an on head, the control circuits of the second, third and fourth cutters and the water spray are identified on the corresponding blocks as

Channels

2, 3, 4 and 5, respectively. While not shown, a sixth channel, similar to Channel 5 and common to the water sprays of the intermediate and end conveyors, I2 and I3, may be employed for operating these sprays. Beyond the pick-up heads, the magnetic signal passes under an erasing head I43 to which a high frequency alternating current is applied, as by the designated 30 kilocycle oscillator, to effectively erase all magnetism from the tape and present it in clear or non-magnetized condition for further magnetizing by the recording head I32 as succeeding skins break the light beam to the photoelectric cell !33.

The wiring diagram of an electronic control circuit I 44 of Channel 1, typical of the control channels of all of the pick-up heads, and suitable for actuating the solenoids Hi5 of the solenoid actuated valves, 65 and HI, and a connected power supply circuit I45 for supplying special plate, rid and heater voltages to all of the control circuits, has been illustrated in Figure 16. As shown in the block diagram of Figure 15, the control circuit comprises, essentially, amplifying and selecting units I4! and I 38 for the in head E33 and out head I34, respectively, of the first cutter 24, which are connected to a common switching unit I45 controlling operation of a power unit I by which the solenoids I45 are energized and deenergized.

Considering the in or lower head I33 and first its amplifying and selecting unit I41, the winding I28 of the head is connected through one of its leads I29 to the grid I of the first section or tube unit VIA of a resistance-coupled, double triode or two-stage amplifier I52 so as to apply thereto a negative or minus electrical pulse induced in the head by the impulse received from the leading edge of the magnetic signal on the tape I25. This negative pulse is amplified and passed to the grid I53 of the second section or triode VIB as a positive pulse. From the unit I 41, the amplified pulse, now negative, is fed to the grid I54 of the first section VZA of a second double triode, a multistage feed-back or switching tube I 55, constituting the switching unit I49. By momentarily stopping the flow of plate current from section VZA, this negative pulse causes the potential at junction I55 between the voltage-dividing resistors RI and R2 to increase and, therethrough, increases the potential on the grid I5'I of a second section VZB of the tube. The resulting increase in the flow of plate current from section V23 reduces the potential at the junction I58 between the resistors R3 and R4,

further reducing the potential on the grid I54 of section VZA and clamping that section at outofi. The initially increased potential at junction I56 is thus further increased, correspondingly raising the potential on the grid I59 of a thyratron V5 of the power unit I to firing potential. This thyratron derives its power from the usal 110 volt, 60 cycle outlet through a transformer TI and transmits this power to the solenoid I45, energizing the latter and moving the first cutter to operative position.

A positive or plus pulse of opposite sign or polarity will, of course, be induced and applied to the grid I5I of section VIA by the trailing edge of the magnetic signal on the tape, forming a negative pulse at the plate of the section, but this pulse is shunted or shorted to the ground by a crystal rectifier or other one-way electronic valve CRI interposed between the sections VIA and VIB and arranged to offer a low impedance to positive pulses and a high impedance to negative pulses. A positive pulse originated by the head thus is blocked by the rectifier and has no further effect upon the circuit. However, the

same positive pulse is transmitted through the amplifying and selecting unit I58 of the out head I34. This unit also has a resistance-coupled, triode or amplifier I59, but its crystal rectifier CR2, interposed between the sections VSA and V313 of this triode, is arranged to shunt or short out any positive pulses in the plate current of V2A, thus blocking the initially negative pulses passed by the selecting unit I lI of the in head I33, but passing any initially positive pulse as an amplified positive pulse to the grid I54 of the first section V2A of the switching tube I55. Since positive, the pulse momentarily increases the flow of plate current from section VZA, thereby decreasing the potential at the junction I and, correspondingly, that on the grid iii! of the second section V23, interrupting the flow of plate current from that section and, consequently, increasing the potential at the junction $53. The potential on the grid I54 or VZA is thereby further increased, clamping that section in conducting condition and further reducing the potential at junction I55, in turn, lowering the potential on the grid I59 of the thyratron V5 below its operating potential. The initial positive pulse thereby shuts on" the thyratron and deenergizes the solenoid I45, causing the cutter to return to inoperative position and ending its operative cycle.

As previously mentioned, actuation of the water spray 84 may be controlled by both on and oil heads in the same manner as the several cutters. However, unlike the cutters, the action of the water spray is only essential on the leading portion of a skin, since once the leading edge'of the skin is gripped by the second grip roll 3Ia, associated with the fleshing drum 7, the remainder of the skin will automatically be detached or drawn from the feed conveyor. Consequently, it is preferred to utilize for the spray only a single magnetic head switch will cut the spray on at the proper moment through a control circuit such as that described for the in heads of the cutters, and to cut oif the spray at a definite time interval thereafter. This is accomplished by the circuit shown in Figure 17, which is tapped to the junction I56 of the control circuit I44 and connects that junction through a variable charging resistor R5 and parallel connected condenser CI and gaseous triode or other valve tube V5, to the grid I54 of the first section V2A of the switching tube I55. The junction I56 being at least at the firing potential of the thyratron Vt when the spray is on, this potential will build up gradually on the condenser CI through the charging resistor R5 until it reaches the firing potential of the tube V5. At that moment, the condenser will discharge through the tube V5, thereby applying a positive pulse to the grid of WA and shuttin off the solenoid in the same manner as did the positive pulse of the out head I34. By regulating the resistor R5, the operative cycle of the spray thus can readily be adjusted to cover the linear travel of the leading edge of the skin from the spray to or beyond the last grip roll 3 Ea.

The power supply circuit I it by which special voltages are supplied to the plates and heaters of the double triode tubes and the grids of the thyratrons of the control circuit I i, employs a transformer T2 connected to the 110 volt, cycle alternating current source and having three secondaries; one, IEI, supplying the conventional 6.3 volt heating current for various of the tube heaters, the second, I62, being center-tapped and converted into full-wave direct current by a fullwave rectifier I53, and the third secondary, I64, supplying the usual 5 volt alternating heating current for the cathode I55 of the rectifier. The rectifier circuit of the second secondary I52 has three leads; one, a positive lead Hit connected through suitable resistors to the plates of the amplifying and switching tubes of the control circuits, another, a ground lead I51, and the third, a negative lead I58 connected through resistors to the grids of the thyratrons. For converting the rippling, full-wave direct current output of the rectifier into the desired smooth, regulated voltages, there is connected in the ground lead I57 of the rectifier a filter choke LI disposed between condensers C2 and C3, connecting the ground lead to the positive lead 155. Also con nected across the ground and positive leads, and in series with a limiting resistor R5, are a pair of voltage regulator tubes VBi and VRZ. By employing a volt tube as the lower tube VRI and a volt tube as the upper tube VRZ, not only is the voltage in the positive lead regulated at the +250 volts direct current which is pre-' ferred for supplying the plate voltages of the double triodes of the control circuits, but there is:- afforded': at a center tap or junction I89; betweenthe tubes, a regulated voltage of +105 volts. Connected in parallel with the ground lead I6], is the negative lead I68 utilizing the same filterchoke LI and a condenser C8 to smooth out the direct current from the rectifier I63 and having a 150 volt voltage regulator tube VR3 connecting it to the positive lead I55 through the junction I69, the tube VH3 being connected in series with a limiting resistor R1. Drawing l.30 volts: from the negative lead I88 by'virtue of its characteristics and having +105 volts transmitted to its plate I10 from the junction I89, the tube VR3 delivers to the-negative lead of the grid I59 of the thyratron V4, a regulated direct current voltage of 45 volts, supplying the constant negative gridbias required for operation of the thyratron.

Using the electronic circuits, above described, forthe operating devices, the electronic control, through the recorder disk I84, is enabled to cause each of the several operating devices cyclically to treat or act upon a skin as it passes the station of; that device. As previously mentioned, each of the cutters, 24, 25, 21 and 28, a well as the spray 84,- is brought into action upon a skin by the impulse generated in its in or on pick-up head by the leading edge of the magnetic signal ini tiated on the magnetic tape I25 by the passage of the leading edge of a skin past the photoelectric cell I30. So also, the action of the cutters and, if'provided with an off pick-up head, the spray is, stopped by the impulse generated in each of their out or oiT pick-up heads by the trailing edge of the signal, as determined by the passage of the trailing edge of the skin past the photoelectric cell. In setting up the cyclic control, the

cutters

24 and 21 and the spray 84, which are designed to act upon the leading portion of a skin, are caused to begin acting upon the skin as its leading edge reaches their stations by setting their in and on heads, I33, I31 and 14!, respectively, at distances, peripherally of the control disk, from the recording head I32 corresponding to the distances, linearly of the conveyors, of the associated operating devices from the photoelectric cell. The settings of the out heads, I36 and I48, of the second and fourth cutters, 25 and 28, which act upon the trailing portion of the skin, are predetermined in like manner by the distances, linearly of the conveyors, of these cutters from the photoelectric cell. The positions of the remaining heads, these the out heads, I34 and I38, of the leading portion cutters, and 21, and the in heads, I35 and I39, of the trailing portion cutters, 25 and 28, as well as either the variable resistor R5 of the on head MI or'the position of the off head I 52 of the spray, depending on which i used, controlling the interrelation of the cycles of the several operating devices and thereby the division of work, are adjusted to ensure complete treatment of both faces of the skins undergoing treatment.

Overlapping of the area treated by each pair of cutters in each treating zone merely reducing the relative work done by the trailing portion cutters, it is only necessary to ensure that each cutter will treat slightly over one-half of the exposed face of a skin of minimum length to enable the apparatus to handle effectively skins of greater length. Such a setting is shown in Figure 8 in which the pick-up heads have been adjusted to handle a skin as little as sixteen inches long. However, if it'is desired to limit the extent of this overlap and thus increase the relative work-done by v the trailing portion cutters, this. may be ,accomplished by shifting the positions of the heads controlling the relative action of the cutters. Since the magnetic signal on the tape I25'"images the particular skin undergoing treatment, the electronic control, once set, enables thatskinto determine both the start and finish of its treatment in each treating zone and the durationzof the action of each of the operative devices. Consequently; the apparatus through the described electronic control can treat successive skins cornpletely in exact correspondence with their lengths and, by always presenting anon-magnetized portion of the tape to the recording head I32, setup a new cycle for and cyclically treat a succeedin skin, immediately following its predecessoiu;

It will be evidentthat the illustrated appara: tus is relatively more expensive than the beamhouse machines now in use and derives its commercial advantage thereover from its ability not only to remove all excess tissue in the form of flesh and hair from a skin in a single pass, but to process skins in much greater quantities and more uniformly than heretofore possible in a given number of man-hours. Thus dependent on quantity and quality processing, it is necessary that any interruptions of the operation of the apparatus be heldto a minimum. The principal cause of such interruptions in existing machines is the necessity for refinishing the blades of the cutters. Unhairing cutters do not present a particular problem since the outer, rounded edges, of their blades are relatively wear-resistant. However, the fieshing cutters are a difierent matter; Even in conventional machines, they are usually resharpened one or more times daily and the same cutters in the instant apparatus would have to be resharpened even more frequently, due to its high output. Did this involve removal for sharpening or replacement of the cutters, as is the usual practice, the apparatus would be out ofoperation a large part of thetime. Accord? ingly, an important feature of the present invention is the grinding mechanism I1I by-which these fleshing cutters, 21 and 28, are enabled, to be sharpened in place or situ, thereby reducing to a minimum interval the shut-downs caused by wear of the fieshing blades.

In its preferred embodiment, as shown in Figures 18-22, the grinding mechanism is com,- prised of a carriage I12 having a substantially I-shaped frame or body I13 formed of a cross-,- or base plate I14 and spaced end plates I15, disposed substantially normal to the baseplate. Projecting through the end plates on either side,- are a pair of spindles or shafts l16-each mount.- ing a roller or wheel H1; The rollers are adapted to ride in channel-rails I18 extending acrossthe frame I and disposed parallel to the, axesof the fieshing cutters, 21 and 28, the end plates of the carriage being spaced from the edges of the rails by bearing plates I19 carried by the spindles I16 inwardly of the rollers I11. As shown in Figures 5 and 20, the channel rails. I18 serve also to support the upper end of the fleshing hopper 96 and within the hopper are normally covered or protectedfrom waste by flanges I88 forming. part of a removable cover I8I.

Suspended from and to one side of the body I13, and disposed longitudinally thereof, are a pair of spaced side plates I82 forming withthe underface of the body a housing. Within this housing is a substantially, H-shaped, supporting block I83, pivotally connected to theside plates I82 toward one end through pins I84 disposed normal to the other side plates, the block carrying below it a stone holder 585 which is slidably connected to the block through a slide plate I85 bearing on guides I81 attached to the underfaoe of the block. In the stone holder E85 is supported or housed a grinding stone I88, the position of which, longitudinally of the block 183, is shiftable through screws ltd by which the stone holder is attached to the slide plate [36.

Extending through and threadedly engaging the connecting or central web I90 of the block i83, and rotatably collared by an upstanding lug E9] on the slide plate, is an adjusting screw N2 by which the position of the slide plate and, with it, the stone Hi3 may be adjusted relative to the block. This adjusting screw preferably is provided with an indicator dial 193 by which the extent of advance or bite of the stone can readily be set. The supporting block [83 is normally held in a substantially horizontal position, in which the grinding stone is disposed to grind the blades of the third cutter 2i, as shown in Figure 19, the block being so held by bolts 595, On loosening of these bolts, the block may be swung to the position shown in Figure 20 for grinding the blades of the fourth cutter 28, being held in that position by the same bolts 19%, then seated in a seat I95 provided for that purpose in the body H3. For driving the carriage H2 across the frame i to enable the grinding stone to engage and sharpen the cutting edges of the blades, there is provided a chain I93 encircling sprocket wheels lill', mounted and suitably journaled on the inner faces of the opposite sides 3 of the frame, the chain having its ends attached to the carriage through a channel or like member I98 upstanding from the body H3. One of the sprocket wheels I9! is driven through suitable gearing (not shown) housed in a gear box 99 and having a drive shaft 200 projecting through the adjacent side of the frame.

As shown diagrammatically in Figure 19, the carriage H2 is shifted, when not in use, toward one side of the frame 1, clear of the fieshing hopper as. To permit removal of the carriage M2, for repair or other purposes, from the chanrails H8 in which they are normally locked, the angle irons 2M, forming the lower sides of the rails, are provided, adjacent this side of the frame, with removable sections 262. Each of these sections is detachably connected to the associated rail-supporting or backing member 293 by a pair of bolts 2%, which may be attached to the backing member by safety chains 2935 to prevent their loss. On detachment of the removable sections 202, the carriage is enabled to be dropped through the rails and removed from the apparatus.

When sharpening of the fieshing blades 29 is required, the cover it! and inner side of the upper portion 9'! of the fleshing hopper {it are removed and the grinding stone [88 is caused to traverse the face of one of the cutters by driving the carriage through the drive shaft 280, the extent of the bite of the stone having previously been determined by the setting of the adjusting screw E92. The cutter, of course, is rotated during this traverse to bring all of its cutting edges into contact with the grinding stone. The grinding may be repeated on reverse movement of the carriage, preceded, if necessary, by a further adjustment of the bite. The supporting block N53 is then swung down or up, depending on its previous position, to position the grinding stone to grind the blades of the other 18 cutter and the operation repeated. Thereafter, the carriage is shifted to its inoperative position and the side plate and cover of the fieshing hopper 96 are replaced, enabling the treatment of skins to be resumed.

Summarizing the operation of the apparatus, skins are fed in succession to the apparatus by being laid flesh side down on the feed end of the feed conveyor H. As each skin travels up the feed conveyor, its leading edge interrupts the light beam of the photoelectric cell lBil, energizing the recording head H2 and setting up the cycle of operation of the electromagnetic control mechanism. The leading edge of the skin then passes under the leading grip roll 36 of the unhairing drum 6 and as it approaches the station of the first cutter 2d, the latter is moved into operative position by energization of its control circuit Hi4 and begins to unhair the skin. This treatment continues until substantially onehalf of the skin has been unhaired, the skin being held in unwrinkled, taut condition during this treatment by the coaction of the cutter and the adjacent or leading grip roll 38. The first cutter is then moved to inoperative position by the cyclic control and the second cutter 25 is brought into action to unhair the remainder of the exposed face of the skin, thereafter also moving to inoperative position. During this treatment, the leading edge of the skin has passed under the following grip roll 3| and ultimately reaches the point of separation of the feed conveyor and second conveyor l 2, at which point the spray as is activated by the control mechanism to detach the skin from the feed conveyor and present it to the fieshing drum 7, with the flesh side exposed. The flesh side of the skin is then fleshed by the fleshing cutters, 2i and 28, which act on the skin in the same sequence as the unhairing cutters. With the excess tissue entirely removed from both of its faces, the skin is finally led from the apparatus by the discharge conveyor it, where it is followed, almost immediately, by succeeding skins treated in the same manner.

From the above detailed description, it will be apparent that there has been provided an improved apparatus for treating sheet material which is particularly adapted for treating skins and is enabled, by its several parts and their relative arrangement, to treat the opposite faces of material in their entireties in a single pass through the apparatus, and to handle a succession of sheets in rapid sequence and as a continuous process. It should be understood that the described and disclosed embodiment is merely exemplary of the invention and that all modifications are intended to be included which do not depart either from the spirit of the invention or the scope of the appended claims.

Having described my invention, I claim:

1. Ireating apparatus comprising a plurality of movable work supports arranged to receive and support work in sequence and each to present an opposite face of said work for treatment, means associated with each or" said supports for treating the face of said work presented thereby, means acting through the presented face of said work against each of said supports and coacting with said treating means for gripping said work to said support and presenting said face in its entirety to said treating means, and control means actuated by said work to cause said treating means cyclically to treat said work in timed